The present invention relates generally to the mechanical alignment of an x-ray system and, more particularly, to the alignment of an x-ray system and/or the measurement of objects in the field of view through the use of precision image content.
As is known, x-ray systems require precise mechanical alignment of its various components in order to assure proper imaging performance. Specifically, x-ray systems require the mechanical alignment of the x-ray source to a detector, a collimator to the detector, the collimator to the x-ray source and other similar registration of components. In order to ensure proper imaging performance, the various system components must be located a respective pre-determined distance and orientation angle from each of the other components. This will provide for images that are to scale and that contain the proper content due to the location of the object to be imaged with respect to the system components.
Current methods for aligning the various components of an x-ray system with respect to one another utilize a ruler or other such device in an attempt to achieve precise measurement. In this process, a test ruler is typically located in the line of sight of the x-ray source and in-between the x-ray source and the detector. Thereafter, an image of the test ruler is taken. Based on the results seen from the image, the size and position of the detector is manually calibrated. This process is repeated until the test ruler is to scale and properly located on the image. While relatively accurate, this process is time consuming and requires significant human intervention, which can introduce alignment errors.
Other prior alignment methods have utilized precise alignment tools to externally position the mechanical components of an x-ray system. These specialized tools have typically been installed on the equipment itself to allow the x-ray team to assist in the alignment process. While these tools provide accurate alignment, they tend to be elaborate and expensive. In addition to alignment purposes, the precise knowledge of position can also be used for a variety of other purposes. These purposes can include, for example, mechanical stability studies, test object measurement, test object alignments, as well as many others. It would thus be advantageous to provide the ability to precisely determine the position of the various components of an x-ray system in a simple, more accurate, cost effective basis.
Moreover, known systems have not had a precise image device. Indeed, these prior systems typically utilize external calibration objects to create a correction matrix for the imager.
It is therefore an object of the present invention to provide an x-ray system alignment process that is relatively simple and inexpensive.
It is another object of the present invention to provide x-ray system alignment measurement tools that are relatively simple and inexpensive.
It is yet another object of the present invention to provide an x-ray system alignment process that utilizes measurements from images to ensure proper alignment of the system components.
It is a further object of the present invention to provide an x-ray system that allows for improved object location determination over prior methods.
It is still a further object of the present invention to provide an x-ray system that allows for improved measurement of object size.
In accordance with the above and other objects of the present invention, an x-ray system alignment process is provided. The x-ray system includes an x-ray source and a detection array. The detection array provides for images having a precisely known pixel size. An object of known size and shape is located a predetermined distance between the x-ray source and the detection array. An image of the object is then acquired with the image having a known pixel size. The location of the object on the image can then be determined and an error can be calculated and then corrected through adjustment of the components. It is important that multiple pixels in the image be covered by the shadow of the object. These multiple pixels can then be mathematically evaluated to calculate either a size or position that is a small fraction of the dimension of any one pixel. The process can then be repeated to verify that the mechanical components of the x-ray system are properly aligned. The operator can deduce or calculation can be made on the image from the image what mechanical components to adjust and in which manner to adjust them.
Additionally, the x-ray system may also be utilized to measure external objects and the dynamic performance of the imaging system. An example of such dynamic performance measuring is vibration testing.
Other objects and advantages of the present invention will become apparent upon the following detailed description and appended claims, and upon reference to the accompanying drawings.